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GFlags

06/12/2018

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In this article

GFlags (the Global Flags Editor), gflags.exe, enables and disables advanced debugging, diagnostic, and troubleshooting features. It is most often used to turn on indicators that other tools track, count, and log.

Where to get GFlags

After the debugging tools are installed, gflags.exe for use on 64 bit Windows is installed by default to the following directory.

C:\Program Files (x86)\Windows Kits\10\Debuggers\x64

If you are running a 32 bit version of Windows, use the 32 bit version of gflags.exe located here.

C:\Program Files (x86)\Windows Kits\10\Debuggers\x86

Overview of GFlags

Driver developers and testers often use GFlags to turn on debugging, logging and test features, either directly, or by including GFlags commands in a test script. The page heap verification features can help you to identify memory leaks and buffer errors in kernel-mode drivers.

GFlags has both a dialog box and a command-line interface. Most features are available from both interfaces, but some features are accessible from only one of the interfaces. (See GFlags Details.)

Features

Page heap verification. GFlags now includes the functions of PageHeap (pageheap.exe), a tool that enables heap allocation monitoring. PageHeap was included in previous versions of Windows.

No reboot required for the Special Pool feature. On Windows Vista and later versions of Windows, you can enable, disable, and configure the Special Pool feature without restarting ("rebooting") the computer. For information, see Special Pool.

Object Reference Tracing. A new flag enables tracing of object referencing and object dereferencing in the kernel. This new feature of Windows detects when an object reference count is decremented too many times or not decremented even though an object is no longer used. This flag is supported only in Windows Vista and later versions of Windows.

Requirements

To use most GFlags features, including setting flags in the registry or in kernel mode, or enabling page heap verification, you must be a member of the Administrators group on the computer. However, prior to Windows Vista, users with at least Guest account access can launch a program from the Global Flags dialog box.

When features do not work, or work differently, on particular operating system versions, the differences are explained in the description of the feature.

Note Incorrect use of this tool can degrade system performance or prevent Windows from starting, requiring you to reinstall Windows.

Important Pool tagging is permanently enabled on Windows Server 2003 and later versions of Windows, including Windows Vista. On these systems, the Enable pool tagging check box on the Global Flags dialog box is dimmed and commands to enable or disable pool tagging fail.